TransformsProvider.UnsharpMask Method

Increases a sharpness of the bitmap by using the unsharp mask technique.

Namespace: Aurigma.GraphicsMill
Assembly: Aurigma.GraphicsMill (in Aurigma.GraphicsMill.dll)


public void UnsharpMask(
	float amount,
	float radius,
	float threshold



Type: System.Single

The unsharp mask amount.

Type: System.Single

The blur radius used to produce unfocused version of the image.

Type: System.Single

The threshold value for the unsharp mask in range [0, 1].


Unsharp mask is a wide-spread technique used by photographers to increase image sharpness even in precomputer times. The idea is to combine the image with the unfocused (blurred) version. This class provides the radius parameter to tune the blur effect. During combining the algorithm calculates the difference between corresponding pixels of original and blurred image. If this difference is greater than value specified with threshold parameter, algorithm adds this N percents of this difference to original pixel (N is set by amount parameter). Otherwise no changes to original pixel are done. As blurred image differs from original ones mainly on the object edges, sharpening effect is achieved.

Using this technique is quite difficult to untrained user as it requires three non-intuitive parameters (amount, radius, and threshold). That's why if you want to provide user easy way to manipulate image sharpness, you can use Sharpen(Int32) transform which is less flexible, but much more easy-to-use.

See Also